A STUDY  OF  A CARBON  RESISTANCE 
LABORATORY  FURNACE  FOR 
TEMPERATURES  OF  1800“  C 


BY 

JAMES  EDWIN  FRITTS 


THESIS 

FOR  THE 

DEGREE  OF  BACHELOR  OF  SCIENCE 

IN 

CHEMISTRY 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 

UNIVERSITY  OF  ILLINOIS 


1922 


/I 


'A 


Digitized  by  the  Internet  Archive 
in  2015 


/ 

> 


1 


https://archive.org/detaiis/studyofcarbonresOOfrit 


Acknowled^ent 

The  writer  wishes  to  express  his  appreciation  of  the 
gaidance  and  help  given  by  Dr.  S.  Putnam  and  Prof. 

C.  W.  Parmelee  in  the  preparation  of  this  thesis. 


Table  of  Contents 

I  Introduction. 

II  History. 

Ill  Specifications. 

IV  Construction. 

V  Tests. 

VI  Conclusion. 

VII  Bibliography. 


-0- 


I 

Introduction . 

The  development  of  the  electric  furnace  and  its  application  in 
the  many  chemical  and  metallurgical  processes  is  making  very  rapid 
strides,  dreat  possibilities  have  been  realized  in  the  past  fifty 
years  and  ever  increasing  interest  is  being  shown  by  the  metallurgist 
and  electrochemist,  who  see  in  it  possibilities,  far  beyond  those  al- 
ready offered. 

Many  of  the  processes  now  carried  on  by  the  aid  of  the  electric 
furnace  would  be  commercially  impossible  if  the  temperatures  recuired 
were  to  be  obtained  by  the  methods  available  prior  to  the  introduction 
of  electricity  as  a heating  agent. 

The  electric  current  is  a pov/erful  metallurgical  agent  and 
great  care  must  be  taken  by  the  designer,  inventor,  and  promotor 
of  the  many  electrical  appliances. 

The  object  of  the  investigation  was  to  construct  a laboratory 
furnace  capable  of  not  only  melting  about  five  pounds  of  steel 
but  capable  of  obtaining  temperatures  of  about  1800“ C to  study  the 


deoxidizing  agents 


-•R^=Eanar^,-'r2r' 

• f • • • ' 


■■ 

.A 


’ ■|*-X  « ' ■♦ 
'’rv‘ 


”5^'fe3 


...  ^ 

4 

. ■->  ■ 


■ -^'1'  •« 

',.  - . I '^"*.  'T  '- , ■ ’ ''-'  '«► 


< »■■ 


w 

"•  -V 

i 


'■». 


.c 


I . ^ 


; ^ *V- 


.«ciicjL;]><n:JJtt  . 

• ‘ !■•  «W 

_iu  tsi  t ’*-« I ! /"' ' •"!  V I " ; It  o M%r»i 

tv'i  ■%  r'*’*' 

Sk*  ‘ . **  ^ r-ir^ 


«i  t*c  XioiT^TnX^f^i  'iJ'  ■{>«  . ' oiflsrj^ 


^ <5? 


' vr 


‘‘.  -X*  .t»3»x<j  t-i'-*  ,jsari>li_ii/Xrii»n^.  *i  ,J  atr:  OhI?  , i,iK,iiicJ{M^<o#£ir^^^^ 

■?  • • ' ■ ^^  . ' ^ '.  ...  ’ V " '■ 


■ (■  > 


i<  • 


kT'  y»  £i»  iifr* 


.fc?  !.«i:u 


-■«  * ’-‘■i'S^t  #4*  '■*■ 

EViiiJ  X^il'  T-lr;  -.  ,Ii  r»  ni-.-ttw  »-v  ’.frf  i.'J  .-^-fifi^  "A 

-V  .;  ‘;T 

;>.  s ■■'.  :;a^  ■ 5-"  ■ - 


JVx  refits V .' 


f*  ( "•”’ j ‘ Iv  • 

i^:  .‘i*  ^ 


>•' 


r_-  ,;^. 


'■  . V- 

. '’■  % fci » ' ’ 1 £ .; » /.'  f » 1 1 

' *'  * • * • . , V 

• -fj  t 


Ilk4f4  >g  *iiV>I-  -'w*!,  t li a' i,^C  <J.!5!ftii-lJ/l*'f -.^, 


U'  if  £ \(s  99nAft  ^ ^ it*  J _<w  a-  l o e 


II 

History  of  the  subject. 

The  electric  furnace  raay  be  described  as  a short  circuit  under 
control.  It  may  also  be  described  as  a metallurgical  apparatus  for  the 
utilization  of  the  thermal  effects  of  the  electric  current  for  an  in- 
dustrial purpose.  By  means  of  the  electric  furnace,  the  electric  ener- 
gy may  be  transformed  into  ’’commercial  energy”. 

There  could  be  no  practical  effect  obtained  from  the  electric 
furnace  so  long  as  the  power  was  obtained  from  some  primary  electric 
battery  as  it  was  too  difficult  to  obtain  sufficient  power  for  such 
a purpose.  Attention  was  turned  to  the  electric  furnace  only  after 
3dison,  Siemens  and  others  had  commercialized  the  dynamo.  This 
afforded  an  adecuate  source  of  power  upon  which  the  experimenter  could 
rely. 

As  early  as  1853  a form  of  the  arc  furnace  was  constructed  by 
Pichon.  It  consisted  of  a series  of  arcs,  set  up  between  electrodes 
of  large  size,  and  throu{^i  the  independent  h^t  zones  of  which, 
metallic  ores,  mixed  with  carbon,  were  passed,  with  the  object  of  re- 
duction. The  actual  existence  of  this  furnace  is  very  doubtful  as 
nothing  but  a few  papers  have  been  found  of  this  model. 

Sir  Hiimphrey  Davy,  in  16(?0,  saw  the  possibilities  of  heat  gener- 
ated by  the  electric  current  and  built  a small  arc  furnace.  Despretz, 
in  1849,  made  the  first  resistance  t^/pe  furnace.  These  first  fur- 
naces were  used  for  purely  experimental  purposes.  Pepys  improved  on 
the  resistance  type  furnace.  His  construction  consisted  of  a soft 
iron  rod  slotted  with  a fine  saw  in  the  direction  of  its  axis  and  these 


v»_,-  ^ i'- ' ...  . 


tWiiooM)!  T^irtsmiii  . 

...  " ''  \ !f’  i 


. - ■:  . - -r.-^  *,••  ,*tt%  i>Kt‘-..Xio  .,■/’  a?am#  u.vtntiJ 

■■'X  i 

f’  ' • . ■ -!r1j  ., 


|T. 


‘•-l?i!7#X»  ix..,-  i4>o.:iTn' C!f»  Ut/. 

*■  ' '■fl  K™  ~ 

^ vt7*9pX<f  i«4M'k  r.A  ^ I • • r<  •.  a.uW  A >A  ali  a.  . W 


liO.i  U' t<JO  ^ ^ \. 

^ ^ 'i'i-r.  .-.|i»;*rfft  t;}  '■■«|‘3i?-^‘35)  VftJ'  #itW. 

•*^1’'’' .Xiv  ®inj.*>f»x^.  ft«4  c*;f  u>fnjj,7;  ,...i*r  -'.{p/jy, 


f 

*¥ 


Pr/'» 


• ■~"^>o^miiU  'i  ' V '.“i  4b(Cf^  hun  cssf^k' 


■■■■  kV' 


!•'  " T?®  - -•?[-  ■ 

^ t)rt7  twn.£|  \9  , •trt^-v4  • 


tyj'v 


><  '• 


.V  v^jJlf.  ■>«*  rtfr;-.-  .’  fJv- 


k ..  . - ’ " ■■<,-  • ^ ' ''r  -'if’' 


T^“:  'iVv 


t* 

9%:  -.'T. '3c  ^a:  ,Xin*»«r  r-ri-r  ^trf>  olXw,^.,, 

- -'  '■  • ^ ^ , 

p ^ . ■ ■ ' f 

■■■  /.  ■ artt  :•>'''  “t'lt't ' 0«f.f  1’.’  (*tt£fiji^i.t(t  f *ia3f!}.4  f^iSS!'  'J^ 

“ ■ . ■ • . 1;  . />  ^ 

, , : • a.  BL  n I.'  ^Ti'rn:r' r>a  ft 

. , . ■/  • -?.f-  ft  ^ ::• 

..  a.  , 


:i 


ly;V  lo  '.’JX^  ft"  -:  ,0®  >X; 


t 

X 


' r • -■  . iT 

Jiir^i£iss»>-.  on«  liAim  ^ ijiik'  X'l^ifta 


L 


■ - ■ -.  ' - . ..  JH  Wi'te’NjlWA; 


■4ui.S  '-^ 


jfM 


y-'„-  ;■  5u>  .,  p »4ci pi|*}ii^_  /<<y4»atf ,?»f3pic#‘i  ^|^|iipy-,:T/n. 

■'*■'•’'■'*  ' '’'''  .•  ' •-  ■!’•  - —I?’  ? 

r'  ,A..-r  \ ^lvlt  1^' m-ii4<«i?|X«JQL*ti,  el^  . %D^4V*yt,  ;f I 


:m 


, , , , , .lS,  _ 

liJ^  * A'fi  .«.  'iViJ* 


£..i.-'  .^J^  ’sv  '0^^,  » 

“iRPSBS^  ;-_iJV.'fifo^r.'::3r^  .ila...  ..,a'Av..L.  ,’k„ 


- ^ 

fine  slots  filled  with  diamond  dust.  The  rod  was  then  wound  with 
wire  and  heated  to  a red  heat  for  six  minutes  hy  means  of  the 
electric  battery.  An  examination  of  the  iron  wire  showed  that 
that  the  diamond  dust  had  dissappeared,  and  that  the  iron  had  changed 
with  the  absorption  of  carbon.  In  this  experiment,  iron  was  for 
the  first  time  treated  by  the  application  of  electric  heat. 

The  first  verticle  type  of  an  arc  furnace  was  exhibited  to 
the  Royal  Society  of  London  in  1878  by  Sir  W.  Siemens.  I t was 
very  similar  in  design  to  the  present  Heroult  Steel  furnace.  The 
first  design  consisted  of  a crucible  surrounded  by  a metallic  case, 
throu^t  the  bottom  of  which  projected  one  pole  of  the  electric 
circuit.  That  part  of  the  electrode  in  direct  touch  with  the  charge  was 
provided  with  a point  of  platinum  or  other  substance  capable  of  resistan- 
ce of  great  heat,  in  order  to  avoid  contaminating  the  charge.  The  se- 
cond electrode,  7/hich  was  connected  with  the  other  pole  of  the  cir- 
cuit, entered  throu^  the  cover  of  the  furnace  and  was  cooled  with 
water.  The  design  of  this  furnace  was  later  changed,  making  the 
electrode,  which  entered  at  the  top,  of  carbon,  while  the  lower  me- 
tallic electrode  was  cooled  wi  th  water.  A covering  of  a very  high 
resisting  material  was  used  for  the  protection  of  the  entire  fur- 
nace. 

Siemens  finally  used  a form  of  furnace  very  similar  to  that 
of  Pichon.  Two  carbon  electrodes  were  inserted  in  the  sides  of  a 
crucible  in  such  a position  that  they  remained  on  top  of  the  charge, 
and  the  arc  formed  between  them  did  not  come  into  contact  with  the 
material  to  be  melted.  Ths  furnace  is  the  prototype  of  the  rever- 


■f^  '■ 

' > V . 


wr  ■ ^ ' 


■'4 


d^tm^aacr^  c.it^yi  *jT^  Jw-i  ->4iT  . ^i«^o+ It , ttlilr  belijt'i: 

fc  ""  " '*•■',  ..  ' 

64  7 !io  «£««•*'  8f*3Toit  jcl'i  -idU  s jtfu  a*<lw 

* V J 


14* r j W^if*  Ittir  *^c  ft<4i/i^;i{ttrt^ 

T . »*'^'|  ""  |^‘ j|| 

‘4W’'  Iniff  a->>cl;  <wli  , 6«t.4«*5Ia>4i  - 2|i  iw  4 ^»o^  Jbir'Jii»IA*ft^tiirta,tv 


T®!  D0t I ,>f  vrt‘Tr»*c*  4fi»14  ill  oii  lU  isr4 

. Id  ‘Ai>|i40ir|i3(4l  f<*4  P1.J  U^U 

M ♦4fT#W'to^  tn^  ttA  ^0  i<R:?  *|c.:diiAV  7i*jAJi«*2 

' '■•.5  ' ' 

♦f  r Aif  r .•  Vi''  Vv-  i-i 

• ‘ • , '"  \ ■ " - 

6 ? r A |rf  Hi»xibeTrtt*6  Hni2 

' V -7^  *^0  :*o;  V »<:<f  t^-%t 

-V  ^ ^ 

Ba  n , r,uir  ill  •»<rt<X*'Vv  '»•  5-a*'t 

^ • ■ ' ■ 9L  1 1 j 

r if’iirai  ■In  tf^4i'?i;tfj»  ‘f'llJC  io  fc. is[  sG  l>ilV  i 

ii  — -.  »n>i  <?»  ’v'trr  oj  r»r6iv*  i .JiWd  #0 

t ■ , - A ^ . ' ■ . , ■-\ 

y*_^  ■•>;::  -li  lo  4Cw*i  6 ■:  i4^iT»  J|'>  lujp?  6»r  P!ot»..-^  ,.##v>li‘0^|i».! 

•i',  '■'■  . '■-  -’iHl 


r M ♦ ■ 'i’9i!''M 

. hr>-it.i.’:.  ’ »■  flr'a-3(l  %i  riorao  I-;?  ii»''XOJr«-  7^;^^ 

‘■^  rtiJi  ti i^^iIbNI' V T-r.a* .'-*-1  *U.*  .-r  «■  ^-*  uf»‘a*L£rt-  •'.<■}•  To  .TBb^aitti  ''.TiiAnte  ■ 

rRi 


■♦'di  v*'^a*''‘*-t  'U'* -'^  • Hr*‘iJ*Lsrt-  ‘T.<‘  To  iSj^Ua**!!  'VTit 

-€f#|4  T^l-^i  ^ -iiilw  ,Ji  4‘:  i <.  ^.‘i  •■  ifSljdW  ,6*0**JO#i  PW<J4jii 

C - , ' V ‘ • 

.^'fM  7T- / - -*i?!*rv  j’P  frA'laoc  6e% 

*•'»*.  iffi'iM  «iU  to  i»^l#Cl63C'T^  4-j  ,t<t  : 

.'■%  * ' **  ~ ‘ ' J ri "' 


' 4 tlMi  i>  V'  ie?  T '<l4,AO(fT. 


^ . ■ ,'-  . . .V, 

i->  If  hSAlcf  -2uU  rl, 


' JU  ft7djiuarsv»*«- 

/;;;.'■  • " ■ ^ ‘Jr:  . rTO 

T.  j?  .‘5-*.7r^.a  •■  «ni  «20  0 ipo  AUi  a'Wv^4.  Qa>«^v't  ©i4  <bi 


.^oniT 


o. 


A'. 


^v  .-6  c^4  T<)  »(3pt#0C0tq  eAl  b3  i'c#rw5  v ,. 

7 ’:'■  ■ ',.()■' 4 i'  »■■;•■■  " ',  ''-’,.«ii 

’ ■'  '‘  <»P.i.  ■'  ' ■:  ' J » . l.yffl 


■)  I 

fe-L’;4A«V!.  :.«4k^ 


, ' H 

' 1^7;  r 


3 

beratory  arc  furnace  such  as  used  by  Stassano  for  refining  or  melting 
steel,  by  the  late  G.  P*  De  Laval  for  smelting  zinc  ores  and  by  ’^eeks 
for  distilling  crude  zinc. 

P.  H.  and  A.  F.  Cowles  were  the  first  to  build  an  electric 
furnace  to  be  brought  into  commercial  operation.  This  furnace  was 
installed  at  Milton,  Staffordshire,  in  1886.  It  was  for  the  product- 
ion of  zinc  from  ores  obtained  from  mines  in  Mexico.  The  furnaces  were 
rectangular  in  shape,  constructed  of  fire  clay,  and  provided  at  either 
end  wi  th  an  inclined  cast  iron  pipe  throu^  which  the  electrode  was 
introduced.  These  electrodes  consisted  of  a bundle  of  several  car- 
bon rods  adjusted  by  means  of  a screw  mechanism. 

The  charge  consisted  of  a mixture  of  corundum,  metal,  and  char- 
coal. A current  of  5000  amps,  at  60  volts  was  passed  through  the 
furnace  and  one  and  one  half  hours  were  required  for  the  complete 
reduction  of  each  charge. 

In  1892,  a series  of  very  important  experiments  were  performed 
by  Henri  Moissan,  a professor  at  Sorbonne,  Paris.  He  used  about 
a two  hundred  horse  power  current  and  concentrated  the  energy  of 
the  arc  in  about  one  cubic  foot  of  space  inside  a limestone  block, 
the  intense  heat  of  the  arc  melted  the  lime  above  and  soon  formed  a 
small  dome  which  reflected  the  heat  down  on  the  chaise  below.  The 
electrodes  were  movable  and  could  be  adjusted  as  the  interior  of  the 
crucible  attained  a higher  temperature.  The  electrodes  used  were 
of  retort  carbon  treated  with  acids  to  remove  any  mineral  matter, 
washed,  calcined,  and  then  mixed  with  pitch.  The  main  reactions 
investigated  were  the  reduction  of  the  oxides,  by  carbon,  of 


.-t. 


* i - r 


<!|^illu!  nb  'U^'\  *-4U0*»tn>'"  id  b9txu‘^A  i/0A5'ac^/»V' t»*5A  wujJs'i**: 

ai.  i't^  i^niiiiii:^  fv1  t*4  .*?  .f  edi 

' • * ■ ' 1..  :*S  • • * 


■ii 


V 


oeU  ^k(n& 


i?' 


P .•  r ’4? . 17  * L ;<#rf  54  ♦‘jtjr  .Tt'  .i-  ItiA  .H  t 

■^,1  ■■'  ' 'V-  ■ ■-  \ 

P4J 


;-fe^  ^t  -.  ^ly  . ■'  ■ '■.:  ■. 


r .li-»  TX 


« ^ ■ • 4 , 


- f 


wyfrt  t,vi*a«:ia't?x!*  ^Ji  ijLiiif.-  , flip's  atfio  T»wrt  Hga'ji 


,fl 


' IV  A ' 

nW/‘i>j-iififf  u ftfj  ^aJhiStoi «';iq  ^.qj.Cais*  ■'' 


i '’<Y' 


. •♦‘inr’’  . IV  \iT  k»i9tj*:tMr,  thc.%  r9d  Vm 


:'ux-  . r . -iti*(j*jt&r>  ir«  ’i 


*A. 


' ■''  ■ - « ;Jiv,v  'f  . OC&3..14-.  |i£&inut»  A jV;« 


.-jo^  6^’.-rW<-  ' ^v;i , - » Tr«<  <f**  hui^^thtndi 

r '^  ■ V'' 

.■>  i-  _ *.  - • -us.  n 


Lftrr  )'**>,  'T.isc  tfj<0^^jo*^tn  4 an*  1»:|  '.: 


^ V ■•  , . * ^ * •.■, 

s'*  M*  . » 


V 


I Sy^  ':  . .•  ' ■ ^'  ' ■ \ ' ' jt 't|, 

j^‘r^t-1'^  - 'i  jL9i  ‘i-t  iK  *'>•,.•  ‘ i'A 

■'"•/  A f '.:  ' ■'  ,‘A'' 

; ^ ^ 

1-  i-VW*'  Hi  ,*  ui,:i.  vfU'»;  9Uii  •»L'  '3x»  ^mtJaX 

■ ' ' ),V  ^ /,..  **»>'  ■''*  ,*•*.•', 

««?  .-#^1*1?  ‘•J’i'/tft  #<!.♦  >10  ■««»  |,#.^a  fi«jm>^ 

r . ■■  ' '*  ■/■  < ' - ■' , 'vif 


^ 0<U  i..  Of  # ijc^joltbfc  atf  ♦X^aqo» 

’ ■ ’ ' ' ' '"}  ‘- 


H 


* ^ - ' * '*  ‘ '2f.„R  'Kx  -V^!!  ' .,  ' ' 

K ' ■ ■'■  i-.ijj'  ’ . ‘'jte’  I®  ^ ' ’,_  ... 

P'1  ri.f.Ti  ;«o*'  r ^t#4ac  j&:oc.tw  c»^  ib*m 

EA-'S.,  ^ ^ 'l*'\  A“B..'’.', 


■'  ‘ '^  ^ *"l  ':  MSm7 

^ •-  ‘"a  '■  ' 

iJL  ^ >w.x,L».-%i-L ii>vC jt^ig,  ^ 


»*.'■ ' 


kJWti  * 4 X 


>/T.>:  n 


chromium,  tungsten,  molybdenum,  uranium  and  titanium.  Also,  the 
formation  of  the  carbides  and  the  allotropic  changes  of  carbon  were 
studied,  ^ith  a current  of  400  amperes  at  80  volts,  the  experiment 
was  completed  in  about  five  minutes. 

The  electric  furnace  has  now  extended  its  use  to  a great  extent 
throughout  the  entire  field  of  chemical  and  metallurgical  processes. 
There  is  but  very  few  cases  where  the  supplying  of  a large  amount 
heat  is  required  that  the  electric  furnace  has  not  been  applied. 


' V "I  ^ ^ • 


t - « _ /'j  j,  Mjf  Jtfi.  «ifri«rt»5o  !ta^tioi«*n’Yui‘ 

I-  - ■ */■,■.*.,.''■■  :,;  "I 

tg  oa  It  W>  V 

T ■ ‘ • rl  . • *(  ■»  . i • ■ . •!»  ,■  ♦ .V„ 

/ ♦ ; , - v1VXi<f-  I ^4u£ji  t'Staj^J  9^ 


■»  ■ £ ■ . . ■'.'  . 

L-  t.M  tv/  %liy;">' r ':  y .™p’*  -*f 


i 


: J 


m* 

itjc  . «4 


ft 


.m'-;  .i^. '. /^  ’. 


;,  , » 


1 « 

CJ  >♦♦.''«  I .S. 


5 


Conclusions 

The  reasons  why  the  electric  furnace  produces  a superior  pro- 
duct with  proper  handling  for  tlie  most  severe  specificationsare* 
First;  The  chemical  composition  of  the  consecutive  heats  can  be 
held  more  closely  to  a standard  than  with  any  other  process.  This 
is  most  noticeable  when  handling  very  easily  oxidizable  products. 
Second;  Less  of  the  easily  oxidizable  metals  will  have  to  be 
added  to  insure  a given  final  minimum.  There  will  be  less  oxides 
formed  in  the  charge. 

Third;  Since  the  composition  can  be  more  accurately  controlled,  the 
more  certain  are  likely  to  be  the  results  of  subsecuent  heat  treat- 
ment. 

Fourth;  Sulphur  compounds  are  more  easily  removed. 

Fifth;  It  has  been  found  that  electric  steel  is  less  easily  in- 
jured by  overheating  than  is  the  case  with  other  steel. 

Sixth;  Alloy  additions  may  be  made  in  the  furnace  rather  than  in 

the  ladle,  which  increases  the  chance  of  thorou^  diffusion  and 
homogenity. 

Seventh;  The  electric  steels  are  freer  from  slags  and  non-metallic 
inclusions  than  are  Bessemer  and  open  hearth  steels, 

Ei^th;  All  of  the  above  characteristics  make  for  quality,  and 


quality  is  the  primary  consideration 


ft  -i  ’ ■ ^ K ! r'  ->  ^ 7r»i' 

iV'„  I ■‘■♦tiffOT  J -i^^•'-t.l- u9frrtfl  f«. 15ti^  ‘eid  ' ■,’''M  j|:' 

t"  ' ^ '-  ■ •' 

I ' si«v«q^  ,.'i  ^ Z£^tMm4  3Rp^ 

i'  , ^ V'.  ’ i,  t ^ ‘ • '■  ^Wy 8Jt&.- 


^ ^ y ' V-  ’<  '•  ‘ ' • '-  'I 

Ui  •«  •f4»4,  i*u.‘  ^.'  o /Xi>vlinB<to 


' ' ' k SAwi^B 

# . ; .*  , t <> . ’ A? ; r*  > _ Miiiof  i'  4 •; W« oXa , 


K . ^,  -.’ ,V . Tffi 

■ t/f  c,  tr^Ai  niv  '*pj  *'r:.  •1 

''^■'  • yV  .1  . Jfi  ;■ 

= tc,'  ,i.:rslp}ti  rr.»r A *?jy»>ri  oJt 

, , ^ ",  "-r  .m 

^ *^V*^*l  ■•*  4^.'  A'|?5 


'.  4 ■'  i ..  «*  •>  * ?«<  : 

t 


■•i  \ 


. iH^crjvl,  'A,flD‘':6,fi'|. 

oil#'  s%(n  94  An  ! *■  .4u«  .#qAXR  , 1^! 

tu  sr*>.  ^Cu-v.^  ,'*5  fjliWK''*'  eUJ  cj 

^ '*  ’■  • 'r  » >■  r.  T|  ' *■ 


ll 

fi  , 


i 'I'*'  .* 

^ ■ ^'- 


• * " ^ ^ 

^ ^ ^ it  • "t  ^X » 6f«)i>'  ti  i V^#  M^hjk^V^OO  TJWitlXljb 

' ■•’4.  .'  . ■ •;  .yi  ., 

f \£  ni  1*^J4  Di'ltTu-ft  Un<>  ttic^jl  iw4  jfx 


A 


\f  ni 

. ■•,o.?4  n .',A  ofht  .»X  JitiX 

Ji  - .-'i-TL'.  .iS»  VfX  \54f  ij}ianr  cf'Jiti! iii-r*  "^CiXl  J " SiJSi  , v^j^i 

<'■'  X' . A Jem  >•■ 


St  ■ 


• ’ - n^-  V 

•T.lt!  ' <-/3  r^5^H<  Itfft’Tit*;  •t':’ ■ ■!  tjX"*-  'j4lfy  ‘ w;. 

> I ' p,.y^  f<J^,i<y-toA?(’ 

j-'  ' ' '•  i 


V , . /.  •bIH 

1 l^v  ij_^,  „ J /•  '•■  ■,»y.''-^ . * •*l.  j;.  '1.  . •; f *■»•]';  '/ 

" '-^r/  '' '>  ^ ‘ avft/i'jjiJn  « f y xxim^ 


■%ni 


ft 

Ijf 


fe*;  '%  r-r  ;^".;:Vv-,  ^'■.-,4  .'  V 

L' , t 1'  • ■*  . t /•  .>  ■»,,  .»C'<J.  i k'A^ 


■l  ..•  ' , ' 
: "<  '■  ' 

p'  ■ ^ ^ 

. • *i  '*  t ' '/■ 

'^<  -',  'V;!, 

■' t 

' • u' re  '1 

' '-V'^ 

,y  >-‘W,  •: 


•■■*■:  crjSaiH"-- 


T 


S 


- ;zo  ~ 


I 


A. 


—y 


6 


III 

Specifications. 

The  furnace  was  designed  for  the  use  in  the  laboratory  for  ob- 
taining  temeratures  of  1800  C.  It  was  to  be  of  the  carbon  resis- 
tance type  with  the  current  entering  at  the  base  and  leaving  at  the 
top  of  the  first  box.  The  current  passes  through  a resi stor  of 
200  mesh  powdered  carbon  which  completely  surrounds  the  crucible. 

The  capacity  required  was  that  a melt  of  about  5 pounds  of  steel 
could  be  had  from  a single  heat.  The  current  was  taken  frcsn  a 440 
volt  circuit  throu^  a transformer  by  which  the  voltage  and  amperage 
could  be  changed. 

The  body  of  the  furnace  was  made  of  a veiry  hi^  refractory  in- 
sulating material  consisting  of  three  parts,  the  base,  the  body  and 
the  cover.  The  base  is  a round  piece  of  fire  clay  20  inches  in 
diameter  and  6 inches  thick.  The  body  is  20  inches  in  diameter  and 
8 inches  thick  with  a tapering  hole  throu^  the  center  as  the  first 
box.  The  cover  is  the  same  dimension  as  the  base  with  a three  inch 
hole  directly  over  the  center  of  the  fire  box,  which  is  8 inches 
in  diameter  at  the  top  and  6§-  inches  at  the  bottom.  The  furnace  is 
20  inches  hi^  and  20  inches  in  diameter.  There  is  a 5/8  inch  hole 
throu^  one  side  of  the  body  at  the  top  and  another  throu^  the 
opposite  side  at  the  bottom  for  the  passage  of  the  electwnGbes.  A- 
romd  the  outside  of  the  fire  box,  there  is  a 3/4  inch  ring  of  hi^ 

refractory  material  for  insulating  purposes. 

The  electrodes  used  were  of  Acheson  graphite  cut  and  fitted  to 


X 


•I 


■ ' v.T  fif-  f 


X;;® 

.'.^  r-f  V 1 ..>'TF' ' 

■ \ 'jr ; ■■"  '^'-531 — 

iM'^'i*W'i  -'^  «'.'’■  «ij{>- >(3‘;-;i  ■ . V 

' '•  •"  i ^ • ' - - ' ■ , , ^ ^ 't ..-  ^‘ 

.«  4t.'  # .ti  ^■r  :■/  ''i\;"  ? -- 

"vt,  '’>»>'  itu  '<«■'•  i'.  ■■  '-'ivv  .'jMf 

'■  <r  . . ./  . .-^jT  ^ T .«!»  ■''  J*' ■ ' 

fk  ^ - -'■^  ’ •■'  ‘5  ■ • 

mV,  :•.*.!-*  ' .< ' < ' J ff  :.t|  c7^  v^/ ,•  •Wi'>'>^f 

'’  * ' ' * >'"  ■ ' V ^ 

‘■.  „y,  '*;  '■ei..  !:.-j--  % ' i t l<l-*  i'p';'**-\rf  "!> ■’^.  t TS>-j^ '■J.j,  7‘lZji'i  iS 

(I  '1  • . . '.  ^ ’V  ' ')T  ? 

" , - ' ■ 'It  ' ,.  11) il' 


Ok  ^ 1 1 }i  •-  •■ 


■si. 


I I’.' 


9^  ' ^ iT  / 

■.  I * '.  ^ .V 


- '.  ■ ' -’X,  ' . ' ,.  '■  r»i ^ 

* :>  liMii ! ..  rt'  '{.:•.  "■' ; H- ^' '*  ^■  <».,f  •■’•  ;^vtc?»U4J 

^ )i|  ’ • ' ' ’y  / " ^ ' S ■ ' ' 

t i»--ff/«rr.i‘'a.--  nf  < , '.n.  PT  ni  .,.  'SPlSfa^W^  -,  ’ 

' ' . ' , /'■  •’I  ■ ■T^i' ) I ■’  j'  V.  :w>vaffi!OT 


/•  s.  \ : . 


f#.Ki“'>  . ..  ,-fif  ^-S1  '’.  .*  -r' 


^ jti  ^ .*  <^/Tw  ^ li  ” ' - • •'  ^ I.  ' ^ -4  ^ * * P ■’ 


' "'*  ' •'^*^,'*’'1’  ■ it'*  T '•'■.*•  <,  ■ ' /.''-'V/Vvii ^ 

yi‘  -^Iftwri'  ’(Hi  -fx*ky  . 

* ' ' ■'  • •'  •?■  .*'.4.  c.(v  '1'^'  i9 

''  '. . ' 


yr.*  J ,n  -t%»’ 


'<A  :ti 


■ ■ J ^>1 

A?).')#'  i^-.--  •■'-  ■ ' ■.  .'■■  "-^fv( . V'^v-  :t»  ^ r.*;’ .[ 

':*.•  ^ X' ' -■  V ,.  • --ij.  1'- ^., ' - ^■  gyfiSEy'  4’WSiM-  f-  {)..  .1 

;!>fV 


,.  I„1 


Ag:fl';i|fciiiii  ‘fr  .ya 


7 

the  proper  size.  The  inner  electrodes  were  cut  from  two  graphite  rods 
seven  and  nine  inches  in  diameter.  The  connection  from  the  inner 
electrodes  to  the  copper  terminals  were  5/8  inch  graphite  rods. 


T>«  «53»v  ^^P'>v>M'3«^'>jr^,  #trr  .©Ain  i^aot^  fi 

‘ ■ . A 

[4j'  i«->rl  A/^ili(}Tt^T  *9!'Mrry  6 .ie^<erl)fe  itl  wrti' 


If.’ 


4 f 


.iA4>c^  9MfVi*sT‘,  <foiil‘^\4  p:»*»  'n;  <tt^  0^*  tlrlJOliOt 


I 


r ^ 

• ..  '* 
► . . .A 


i.'  i '■■ 

■ ■ ii  . .r.!.  «'> 


••■•'.  I ■ J ' ' 

'■-  .1*  ^.1 

^ ’,'V 


mAj  a 


^ ‘ 


* 4 

■ 


1 • 


Sf 


-.1 


f. ■•..■- 


<>  ' if-y  ’'  < ' 


f '■•  ,f ’v»  t.. 
•’  M’  4 


*» , 


i'.'^  V -■>-«  ^ ■ 

V :...f,' 


> - ■ V^* 

V^.i 

. • •’  '>  ■'  ■'■•'*• 


- * ■ • . I ■■  . i.'  ' ' ^"  ' 

■''  .!'  ‘ '..i-  ■"■' 


.-wi^  »■.■'«■  ., 

A«  'A*!-, ''iiKr.'Vi  *;',; 


'f* 


ii^ 


i >.V  - k ^ k.ik'a 


:,T4,a:;^.ky:faa)pr^-?i 


IV 

Construction 
The  Body  of  the  Furnace. 

The  body  and  the  insulating  ring  were  made  by  the  Ceramics 
department  of  the  University. 

The  top  and  plug  were  made  of  55^  of  calcined  flint  clay,  8- 
30  mesh,  35^  of  Georgia  Kaolin,  and  10^  of  Tennessee  ball  clay. 

This  mixture  was  mixed  with  water  and  allowed  to  stand  for  a short 
time,  then  cast  into  molds  and  placed  in  a damp  closet  and  allowed 
to  age.  It  was  then  dried  in  air  and  fired  for  48  hours  at  a temper- 
ature of  1410*^  C. 

The  body  was  made  of  50^  coarse  grog — all  on  10  mesh — , 10^ 
coarse  grog — all  throu^  10  mesh,  and  40^  of  Hickory  Saggar  Clay, 

This  was  mixed  with  water  and  allowed  to  '*wedge'».  It  was  then 
molded  in  iron  rings  and  a central  core  used  when  necessary.  After 
standing  in  a damp  closet  and  ageing,  it  was  then  fired  at  1410‘’C  for 
48  hours. 

The  inside  ring  or  insulator  was  made  of  70^  of  calcined 
Bauxite,  20^  ASnid  Mississippi  Bond  clay,  and  10^  of  Georgia  Kaolin, 
This  was  finely  ground  and  treated  similar  to  the  top  and  body.  After 
the  firing  process,  the  forms  were  cooled  very  slowly  and  the  phy- 
sical constants  taken. 

It  was  found  that  the  total  shrinkage  of  the  body  was  6^  and 
the  cover  7,14^.  The  water  plasticity  of  the  cover  was  28^  and  for 
the  body  30^.  The  water  plasticity  of  the  ring  was  27.5^  and  the 


f 

'u*z.  ''' 

. 90A£nx/^  \itr  ’'e  ^JSce 


'•;  . ffJT  “it*  «i !tt rtt** ft p [.yilP 


-C'.  . ' f..^;  t ;f  'io  *65  to  •jfv.jr  4»*^0>r  u*fSS,  ^ KiSf- 

’■  r"  ■■  ■ ■ . ■ * - ‘V,  •,  • '.‘>1’^  ■'  ^ 


w » 


k ^'‘[  CC 


r 


f'  — -- 


. '^ ::  w 


■<;5VM<o  tolk  fra  5;  f ■■  atR  n»:  dfix^t'oxtiw  tf-v 


!l.  i 


f 


, jt4f&  ;^OXc  <H»wU>  ' -«■  I I )Wi.'  ^i^6(^^  <^it:{^c‘h  u rVt  ,-«ur>4 

V'  ' r’tiim  '*'*^^ 

^ a-troli  'I  tL'*t  .iit?’.  bti#?  *r}^  ni  ‘i-.itr  •#■#  ai*  ''  fife  ' 


' « 'I,  -Tj't  frft/?  fU  f»i  Hltfr  ii^4J  5> 

i V*  ■■•  ■ '■  ' V.  ‘ * '*■  ' 

^ .Q,‘o:i>i  10*  itiriif 


\’i  \ 

J 


■* . ■■  ''  f 

r,  - 


V,  U 

t'v  I ,*-RiiR«4l  Oi  CO  i*  :■.-«<  *3t4K'0  ''C5 'tp  »lPP-'l3 

""■•iW 


1^  1 

4 


IS'  *'*  "'’^(it  j- 

/ a ;^«ji2kjV  '.■?  oi/f?- ^ 

VJ  i'  1 . • ‘v^ 

ti  *t-  x,r  %»vc»  fl  f' vi'*^ 


' : •;  I ■ ' ' ' V 


• ' •:'.  • ■ =»  ’ '.'i  . ^ V 

Mjt'vv.  O *fc'  IV  T"'t«t{40l  t-  ^ 

-'^  ■ ■ >■'.;  

,%atn  frflftT,  i;  v " 

r -■  'V^  ■ 'V  . • /.  , ;..•"*'  '•>  ■ •''  ; 

'5-  >i‘jf  ac7  i>9  4«lXtei5i  1*41  ♦fc‘D.  Jjfm'jMump  fli>v 

JhfOJ*;©  i-r^x  ftcrj'A  »s4X^  ^XaXl  J 


• -JT- 
'^1 


vS 

3 


,-5' 


\ i^'■l 


j' 
( A 


t"*  *. 

i' 


H‘ 


,Sk>*l:t^  ^fcrjauvo  >tco£&  n 


Uii  Yb  9CU  tQ  . '' ^.''3 

O'K  t^w^rerco  frtft  "V 


^ . . 


’ J.riri  ;-.ii.‘V^.  fcrx  atfiV  Yo  x/  .t  ,'^<ii5  ijkul.  I'rft  ’ 'vij  ■ 

M N V « ' '^B_  '.  1 


:syy^Xl3SX!:i((XV:£f 


SdaJ  : . r;-'- 


'i;  .’iv  • 

I I U ‘ 1 1 


V,'i  . 


9 

total  shrinkage  was 

Cons  traction  (continued) 

The  Electrodes, 

Anthracite  coal  and  a distillate  of  pitch  were  used  in  the 
manufacture  of  one  set  of  electrodes.  The  coal  was  of  a hi^  grade 
anthracite  coal  with  about  80^  fixed  carbon  and  less  than  ash. 

This  was  ground  to  80  mesh  and  calcined  in  a gas  furnace  at  a temper- 
ature of  750  C for  four  hoors.  This  reduced  the  volatile  matter 
to  less  than  !%•  By  this  treatment  of  the  raw  material,  the  shrink- 
age and  tendency  of  mud  cracking  was  greatly  reduced. 

The  binder  used  was  obtained  from  a hi^  grade  coal  tar  pitch 
with  a fixed  carbon  content  of  over  40^.  This  was  placed  in  an  iron 
pot  still  and  slowly  distilled.  The  distillate  was  a heavy  jelly 
like  tar  with  a melting  point  at  about  100*G.  The  distillate  was 
redistilled  and  the  melting  point  of  the  distillate  lowered  to  80° C. 

The  carbonaceous  residue  was  then  heated  to  a temperature  of  about 
1100° C for  three  hours.  This  completelj^  es5)elled  the  volatile  matter 
and  reduced  the  per  cent  of  impurities.  The  residua  was  ground  to 
80  mesh  and  used  as  the  body  of  smother  set  of  the  inner  electrodes. 

The  finely  ground  carbon  was  thoroughly  mixed  with  the  binder 
to  form  a pasty  mass.  Both  of  the  constituents  were  heated  to  about 
100° C before  mixing  to  insure  a homogeneous  mass.  The  paste  was 
then  firmly  pressed  or  ’’rammed"  into  the  circular  molds  for  the 
inner  electrodes.  The  upper  electrode  mold  was  &§•  inches  in  out- 
side diameter  and  6 inches  in  inside  diameter  and  1-|-  inches  thick. 

The  bottom  mold  was  7 inches  outside  diameter  c-,nd  4-^  inches  in  in- 


‘ ■‘■^ 


T- 


HJ,?' 


{•A  l^rUoyc'J ' ffiiviiii-JftIfftWO  . 


*^''  , '4^  «•  »<cvl=|  -to  ^'icw:  Auofi' 

I'V  ' ' ’r  • ■ ','  ’■ 


4:: 


-‘  ^jua  ?4J  ?'r  -.•'ff  |i,  o tviL25  4fJStf  lACifi  .«i:iisJ>.'ip&i£:|.  •‘'‘'Pbii- 

• • *>•  ' ■ .'•  Yr.  ■" 


•'■  f V‘,*>  ti^  itccr:  ^,¥t£  C^  '■..■j-  • ii*?**' 


rK 


* J ‘^  { fi  * ' ■ ,r  . >i 

*.'  ; , ■».p'’-f-.  .-.I  r*-.  .»t.  Nf  3;.»i*l,  V* 


>-  ■ ^ ■•  '.  '■  - \ ■:- 
....  ■ ' ' ■ - '«4  u 


J 


?i  * i <^l};.T;^’‘i<5i;i  x.  .n.'A  g,ji»  {.if?*  ;-^  tijf 

>-  . •*■"  '.  ■ . ' ■ ■ ■^  :v  . ■''■  ■■ 


' '•-  i • 

^ li  :^r  .•-»  ■ Uy''  V 


*■  I 15  ',t  ’'VI  iw04ff  /ttioq  jj^sf^iVr'.  c 


4’C. 


cfl  V-  . 2, 


■ 


t-i.l  /*“-’•  *t,i  •?aVV'>’5^SfarVff?  ij  6.  .*  • ni >' AVxs;£'li{f  ^ 


tr  u*  Sr’i  Ux  vdfy.r  W c :•  *'?r ‘vu,  ,oi 

■■■  . , ,.  .'  - ^ '.  ■ '•■V'  ; ■"  

•'.*  .i-  ''i  *\v  :-i,  .^oU  l"i£K^csl  "i,>  » ‘V* 

-,'  ■ w^' 

. ■t''.,"!'*sk^  !•  <^^  I' *,  ,'‘ij  T?- I' • wi;*  tiH'  kfi'ffSf  jti — •'^'‘-■■= — ' 

.-IJi  r |4ftclr  •:L'*ijifi^iijl^>  a i 0«S!^  - 


< ■ ^ 


.'i 


!•- W 


',  = A. 


Vi*.  . ••  ty*fi  •*,  ■■•  ••■'•  ,»•  '.V’j/i  : ••  ^ ,A','(3L 


Yic..(i-i*-'‘®'*  ,f'SI.*«  ,«4;' wnJ,  ’’ift.'akx^ 

. «;  ■•...  fil  ■W^  : 

.'••  ■ V - Y , f-':  v>^v- ..iy  'i 

' ■•  • * ■'-.i.  tV'm  • ■ -.  .;  .* 

' ''<£J 


C^4-  .V  .V- 


'I' 


'.ftk  ' \- 


.{<£ 


10 

side  diameter  and  1-|  inches  thick. 

After  the  mass  was  firmly  pressed  and  allaved  to  cool,  the  raw 
electrode  was  transferred  to  a fire  clay  pan  and  completely  covered 
with  coarsely  ground  calcined  anthracity  coal  to  prevent  oxidiation 
and  to  permit  the  escape  of  gasses  during  the  calcining  period.  The 
pas  was  than  placed  into  an  oil  muffle  and  heated  very  slowly  up  to 
a temperature  of  400®  C for  four  hours.  The  temperature  was  slowly 
raised  to  about  850'' C and  held  at  this  temperature  for  from  six  to 
ei^t  hours.  The  fumace  was  then  shut  down  and  the  electrode  allowed 
to  remain  in  the  fumace  over  ni^t  inorder  tiB  t it  be  cooled  very 
slowly. 

The  carbon  from  the  coal  and  the  pitch  were  treated  by  the 
above  process  in  the  making  of  the  electrodes,  but  owing  to  insuff- 
icient pressure  in  the  ramming  process,  the  finished  produce  was 
somewhat  porous  and  easily  crumbled. 

In  order  to  get  a more  solid  aid.  compact  form  of  carbon  for  the 
inner  electrodes,  two  pieces  of  Acheson  graphite  rods,  seven  and 
nine  inches  in  diameter,  were  obtained  from  the  International  Acheson 
Graphite  Company,  Uiagtira  Falls.  These  rods  were  cut  into  discs 
l-^  inches  in  thiixkness  and  turned  down  to  the  proper  size. 

The  connection  between  the  copper  terminals  and  the  inner  elec- 
trodes was  made  by  a 5/8  inch  graphite  rod  20  inches  long.  One  end 
of  this  rod  was  ground  down  and  fitted  into  a hold  in  the  inner 
electrode  and  the  other  w.s  clamped  to  the  leads  from  the  switch 
board  by  means  of  a thin  copper  sheet  bent  around  the  rod  and  bolted 


^VT'.  ' _ __  .. 


:.iCl 


n 


r3r:y,r 

'.  ':■  « ■ * :-l  'J 

-V  ^ • - 'jj/  ■.: 

, l^t.  k-  -.titir  •*  n *»,>->■ 'll  0ft}  t’ 

•«  ' ’ •'  ^ •:  ■,'-  ■ ■'-  '*'  . ^ 

:%*•,  ' - ■'  i'  ■ /V!  -'  '\^-„ 


•r  r: 


r 

II 


. .Tf! 


\;  • ■’ ‘ C . "■-•  'T* ,/'.'  V-“  '■  •VJ'lt.K’''? " 


?|  ..'  ccn«u:«  o/tfr  t^4  9/t  ^J  * i to  tlA  rt.-jS4  fctf  II*' iitf  iJi’  V 9i’7 

X ^ % ■ ••*  \ 

\frvF9  a.  \*  #fi  ' . >t^-  • -iJsoi  y>>  ^0  -.^X  \ 

. ^*'  ' ' '* JMBti 


j oT  4?  : «\,n  jfcl  ifijal-: t.  jiSf>;_^,.*^^''  / Jiititt -5^d5^  4Pp40>  u} 

L.;-^  ’ \ , 

l/«(  tt»;i  fre^r  •»it;Sc:-n 

f y»ir.  ■ ■ •^  ■' 


’,  9iif  ^-f  tr:*v  fijf:  j^loj('ri  V > ^tnn  r 

“ ■ '-  -tct).'}  • - 


* ^ "'if  Ic  . H.  ju  fcr,i  4“1  y«to8,v*tit 


;-i 


'j 


'■^1 


•rf3 


, rii ' ».  r,ai,'n.«  ,/&>!?  jiwltijt 

>■  ^ * ^’li  '. 

ifr.  r«1«tvTO  >5*.  '>  '!  ' 

■»■*"■-■  ■■  ...  i' . ,.'• 


t ■ ^fci'k  ,' K>.  Uiltn  . TfOt.  u i»;;)'e4  rf 

•:  lKa^“  ' 

^^u*  ttvv  .1'  , ■ t.  :"-3  . %4-:  ,9»b€7,S0*^Ia  -spirni  J, 


i'l  , U ‘ . ■••■  . : 


*7. 


5,^ 


7"  4 ■*  r *»’ 


i J. 7 /mjfc  it  nijiw.t  ijijl.  5ii*/jy*'Utgi^  . ' 


’'  T 


i».  !*»  ‘fit  .-Li-*  i ,?i:-  -oci  or,  Jk<»{  #i  tyf 

.‘i  -.j  , . ,'  ^ ■ '' 

'tunai  iri  14.7#.  * 04ri  .fc.'JW' A,tv; 


F ...1  . 


.'  '‘i'r 


..A*' 


■ I-  /.' 


'*-‘*r  ..V  J ■"■  T • ' - “•  • . .'i.  ' .^  '^''li.  '•  '■ 

" '.  ■■ ' - ' - ■ '■.  ^ ' ■;■  3 1 


' T<  * 


: -mi 


.■‘>  I 


...  13  . 

J0^:'  r"' **«'?. V*;^ 


■■  .x^s 


I , 


i) 


'yV-  ■ • 


11 


to  the  terminal.  The  electrode  and  terminal  were  cooled  by  water 
system  throng  a thin  walled  copper  tube  wound  around  the  electrode. 
The  resistor  used  was  200  mesh  Acheson  carbon.  This  ccmpletely 
filled  the  space  between  the  top  and  bottom  electrodes  and  around 
the  crucible. 


-.1. 


j... 

. ■.  I' 


xfi  : :,k^ r) »•’.•  ‘ 'jji# ^ w ^ ". : . *'i  *1 

* •'■■-’  ■ "■"■'  •'  ■'  '•:  > '■  ^■- 


^ :;r 


j/w  ^ 


N'j'  id^,  - •'  ■''  • ‘ .,  <■*  ' .'•  ;•  ’ '■■*•  -'.^^y.  . r j. 

iXuifc  uiu  /i  % ' •br  >i 

'■'  - .'  ■ '"  ■'s  .'>JS . '■'  " ‘. 


™«->> 


fi‘'  ,*v 

E*»  ..'  ' . -»  • 


If  ■ .* 

L.  - 


i ' I 


.»•  -V  ■ ' 


H W,m  >1*.  ■ * %r~i‘  ft’"*  ■ 

7*r/  i- Vf**’"’ ■■*!► '"•  * ’{*j 

.... 


^ J*  y j . •■’  ’ ■’■•£ 

•it'  '•-■’■  • 

'^'  ' ■‘  'I*'  ■ ■'■  'j'.ii.'- 


' Sk 


■ V-'  V_S  • f " ; '’ 


*-S  r^*v  ^'  • f- 

. , . dL  i * /A.*  • * ' , i 

f'  '*.  * i .'i 

■ * ‘ ^ '■■>--> 


' ' > 

^ a 


iSti  'ifi.-'  '^'i 


12 


V 

Tests 

The  flirance  was  connected  to  a 40  volt  circuit  of  13  and  one 
third  K.  W.  At  the  end  of  45  minutes,  a temperature  of  1200®C  was 
obtained  with  a current  of  45  amperes.  In  one  hour  and  twenty- five 
minutes,  a No.  24  Segar  cone  was  melted  which  m^nt  a temperature 
of  1510*0  of  over.  This  took  a current  of  50  amperes.  A fire  clay 
lined  graphite  crucible  was  used  and  did  not  break  down  to  any 
appreciable  extent.  Owing  to  the  large  exposed  area  of  the  gra- 
phite rods  to  the  air,  they  became  white  hot  and  burned. 

The  current  was  then  changed  30  volts  and  20  W!»  At  the  end 
of  one  and  one-half  hours,  a temperature  of  1500^0  was  obtained  and  the 
current  again  changed  to  40  volts  and  13  and  one-thire  K17.  The  tem- 
perature rise  was  130**  0 in.  15  minutes. 

The  carbon  rods  were  shortened  and  refitted  so  that  the  cooling 
coils  were  as  close  as  possible  to  the  outside  of  the  furnace.  The 
rods  were  packed  in  alundum  cement  to  prevent  the  oxidizing  power 
of  the  air.  The  cooling  system  and  terminals  were  insulated  with 
sheets  of  asbestos.  The  graphite  cracible  was  replaced  by  a 
zirconium  silicate  crucible  with  a melting  point  of  about  1800^*0. 

A current  of  30  volts  and  20  K7/  was  used  and  a temperature  of 
1500® C was  obtained  at  the  end  of  one  and  one  half  hours.  At  the 
end  of  two  hours,  a No.  24  Segar  cone,  which  has  a melting  point 

of  1610* C,  was  melted.  At  the  end  of  two  and  one  half  hours,  the 
temperature  was  at  the  melting  point  of  a No,  29  Segar  cone  or 


. ‘‘  '■  ’ ,,  1 1 


■-;,‘f;  V^  ^,  ■ J; 


fT:#r  9^tt7 


« 


■ ^1.  h ■ . ^ ' « r»r  .fn 

1'.  ..y^  •*  . •.»  15  nitlfffJ  i K'.f/  W fti'd-’M-.'i?  ,Bf>'^5' 'V  ’ 

•'*  ■ i V.''  ' ■ ■',  * >‘  ■ ' \ 

'■'  '*  .''■'  ' "'  ' ■“  ' • ' ' ■ '^>■,■^'*'■''^5:  ''■■■  '.i  . 

^t;-  ^ i J::;?  Vi>^y^  --iN  "i?' W.^'■ 

.V"  ■ "■ 


•i,  ‘/4b  ;»«■*■'  1 K- #«4tr  ."3 

■ U5  ^ ■ . ' ■->  . *^' •.'  ' tjaT^  'j 

•^  * - . , V,  '‘.V'  v*ira  '♦i 

V.’ .' e ? r ^s/,v.? '^.'.Stl 


f*'  \- 


• • ••;■• ? •’.'0  Afifc  , iU'v-;  tfm-  ,' 

J-.  _ • I ..’i?-'  '^"V»r'  /’'  ' 'I.'  '.  >.  , ' *':*  ..'  ^ 

■''■■  '')•  ' crv;>  ^ik.'es  ^-?  l{i!| 


^jr'  ' ' . . 

. w.  v,r  . 

•,  / , ■ .3 

: ■ id:..*  i ‘ 


-*4i<M1  ./.  t k 


above  as  the  cone  melted  and  the  crucible  fused.  This  would  re- 
quire a temperature  of  from  1750“ to  1800^0.  The  temperatures 
up  to  1700“  C were  confirmed  by  means  of  a radiation  Pyrometer. 

Some  difficulty  was  encountered  in  the  use  of  the  radiation 
pyrometer  as  a small  carbon  monoxide  flame  burned  at  the  hole 
throu^  the  cover. 

Th©  furnace  was  taken  apart  and  carefully  insi^ected.  The 
body  and  the  inner  electrodes  showed  no  ill  effect  of  the  pre- 
vious heats.  The  insulating  ring  was  cracked  but  still  fit  for 
use. 

The  electrode  rods  were  replaced  and  neiv  connections  were 
made  between  the  rods  and  the  inner  electrodes.  The  bottom 
electrode  was  made  air  tight  with  alundum  cement  and  the  carbon 
rods  packed  in  stlra.mite  to  prevent  oxidiation.  A new  zircon  cru- 
cible was  used.  A layer  of  selmanita  was  placed  in  the  crucible 
to  prevent  the  segar  cones  from  forming  a slag  with  the  crucible. 
Numbers  32,  33,  34,  35,  and  36  segar  cones,  with  melting  points 
respectively  1770“  G,  1790"C,  ISIO^C,  1830“C,  and  1850“C,  were 
placed  in  the  crucible.  A current  of  30  volts  and  20  EV  was 
con  lected  with  the  furnace  for  one  and  one-half  hours.  Tnis 
current  was  then  changed  to  40  volts  and  thirteen  and  one- third 
K?;  for  20  minutes.  The  crucible  collapsed,  causing  the  re- 
sistor to  fall  and  break  the  circuit,  and  ended  the  test. 

The  furnace  was  then  cooled  and  the  contents  of  the  crucible 
noted.  It  was  found  that  the  crucible  melted  and  fused  with  the 


silmanite  to  form  a clinker  like  mass.  The  fused  mass  and  the 


-et  i'XvOT-  riJ^  , «^i  iica  J&otX«ir'fitt>d;  lAi 

'A  ^ ]"  -'•■-  w, 

, • O.*^0fcl- txj/Oa^rr 

- ;>j'iJl;a^  !'  tti  tii^i»!  ^ 0 'O(iV|.  uJ 

' ’ j . , » ' * ‘ ■V 

i ■ ' ■ ' '*:■-.  .:  ,,  ■ • W.  .*!  ' . 


‘ * ,;r  ■ ■,, 


W I 

■f  ■ ■■ 


, V 


.'ft 

" 1 1 1.  ^ 


t ‘ 


ojr.  .i'-f  .v.  ^ ,rt  Jitiz  je»».<4U 

- ♦ '■  .'  ' ’"'  ^'i:M 


m 


'4  ipi.tli  1(JX  cr  x^aii  : 1 


-i.X-  XiK‘c  r*'^  ’'*'  tl>vt9  C ^ ''.it  ijM-ti/. 


■ ".'  oi 


'ta 


't*j.A'  9rt&Uo<>a.-^CJ  Wt-tt  i;c6  >xvi8fr  . tji'TjfcV  uhox  A^iia-^Ufa  o/cjvf^-.  ,/3 

-."  V ' ■ ’ - ^ "-  ,':i' 

k'  .*vlW'S''>0'?X#  :«‘C'U  *<?/  BXk®7  *fU- 

. * ' I -T  . ',,  ,il!  ■•  , \ ' ' - ■'  ^ ' I 

' • '■.  - ,, . V .,  . '«  . • . 

i« 

, I 


I '*  W'iU:  ftSI  «atfu»Jt.- U'  >t^MJ  tU  ■ iiCfti  c<i^ 

V A'  'l  ■ "^  . ■^  ■"'  »-  ' ^ 

^oUaUXxo  /f'ii  Vi  I i i khcn. 


,■•',■  *■  ■ ji  - ' • • '>^  'j 

>'i  vfj  4t;.  »aw  9 *ixtA4jia*.tc*«^i<t(‘''4  . «mp-  v-? 

.^''’5';-j.,: -■  '.-.V  . ' o:-.'  ' r j. 


4lv  M a»ni>o  «»ilt 

' ^ ' ' ' •'  ' ' T : ,'■ 

OH:  ,%^  rct}  •:.  t.cv.  BC  »>*,  %*«' 

^ . :,  ‘ ' V 'O 

.>/  A ^ 


\ 


-y '•'•"■ 


»>/'r-T?7  C^-  t'r  '’rX^v  a-f 

^ r ' « *■"  ^ ,'  ' ^ ' -. 

, ‘ ‘"i  .' ”■  f*'  ;.' 

J.  hisr.  #■  tnA.-ll  ®**it*'^ 

A .-»  ''  ’ " ' • /.  , •:*'f|- 

.j.'J  '■  . , '..  '■'  /»  • \v ;'■*,•  ,•  V*.  ' ■ 

. ■■  •'  ..  :■  V"  .' 


ll 


v r:*  '•'it  t«|^^ 

**  ‘ ^ ?•  •twA  /■  f ' «, 

■ ■^•  SI,.-...  ' ■ ; . 


sr,. 


k-'  ' . 


■w* 


T 


itiir^- 


v;< 


..  ^ 
‘-*A 


14 


carbon  resistor  was  carefully  examined  for  traces  of  the  segar  cones. 
No  unmelted  cone  was  found  but  small  pieces  which  resembled  parts 
of  the  cones  were  found  in  the  clinlcer. 


VI 

Conclusion. 


15 


It  was  found  that  by  means  of  the  carbon  resistance  type  of 
furnace  tonperatures  of  1800° G and  over  could  be  obtained.  These 
temperatures  were  confirmed  by  the  melting  of  segar  cones  wi  th 
melting  points  of  from  1800°C  to  1850' 0. 

The  current  could  best  be  conducted  from  the  copper  leads  to 
the  inner  electrodes  by  carbon  rods  about  one  inch  in  diameter.  A 
rod  5/8  inches  in  diameter  easily  becomes  heated  and  considerable 
care  must  be  taken  in  cooling,  A water  jacketed,  copper  electrode 
may  be  used  to  good  advantage, 

A zirconium  silicate  crucible  cannot  be  used  for  temperatures 
of  1800® C. 

In  a crucible  c pable  of  withstanding  the  hi^er  temperatures, 
steel  could  be  melted  in  small  amounts,  if  a current  of  40  volts 
and  13  l/3  in,  were  used. 

Owing  to  the  fact  that  there  was  considerable  delay  in  the 
making  of  the  body  and  insulating  ring,  the  tests  of  the  furnace 
>and  electrodes  were  not  complete. 


16 


VII 

Bibliography 

Furnace  Electrodes  practically  considered, 

R.  Trjmhull. 

Transactions  of  the  American  Electrochemical  Society. 

21-397-1912. 

Electrode  construction  for  furnaces. 

Chemical  and  Iletallurgical  Engineering. 

9-67-1911. 

Furnace  Electrodes. 

Chemical  and  Metallurgical  Engineering. 

8-391-1910. 

Standard  Electrodes  for  Electric  Furnaces, 

Iron  Age. 

98-1369-1916. 

Graphite  Electrodes  in  Electrometallurgical  Process. 

C.  L.  Collins. 

Transactions  of  the  American  Electrochemical  Society. 

1-53-1902. 


Electrode  Efficiency  of  Furnaces. 

Carl  Hering 

Metallurgical  and  Chemical  Engineering. 

7-473-1909. 


Electric  Steel. 
Metallurgical  and  Chemical 


John  Mathews. 
Engixieering 
16-10-5/15/1917. 


The  Electric  Furnace. 


J,  TT.  Pring. 


Electric  Furnaces  in  the  Iron  ;3ind  Steel  Industry 

Rodenhauser  and  Schoenawa. 

Electric  Furnaces  and  their  Industrial  Application 

J.  Vright. 


Discussion  of  the  Electric  Vacuum  Furnace. 

Collens 

Transactions  of  the  American  Electrochemical  Society 

9-1906. 

The  use  of  carbon  in  the  study  of  temperatures  in  the  electric  furnace. 
Transactions  of  the  American  Electrochemical  society. 

6-1904. 


Manufacture  of  Carbon  Electrodes  for  Electric  Furnace  purposes. 
Chemical  and  Metallurgical  Engineering. 

22-741-1920. 


